Approximately 20 major malformations have been identified from the malformations registry data base for future investigations. Staff have been recruited in New York State and the protocol has been developed by investigators from NICHD, The New York State Dept. of Health, and NHGRI. Cases with the major birth defects of interest have been selected from the Congenital Malformations Registry along with suitable control subjects. Data from the Registry have been linked with the State's newborn screening program to identify filter paper samples for the first group of subjects. The first defects of interest have been selected;the links have been used to select filter paper samples;and DNA has been extracted from the filter paper for analysis. A laboratory has been selected for DNA amplification and genotyping. The first samples have been sent for genotyping. Concurrently, the New York State laboratory is performing gene sequencing on the first gene of interest in one birth defect.